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Author Topic: solar panels ,,worth the time and trouble??  (Read 4678 times)
Joe Camper
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« Reply #15 on: May 12, 2011, 11:13:05 AM »

Boogiecat

very slick idea dedicating a inverter for the fridge then triggering it off the thermostat eliminating an unnecessary idling unit.

Very slick very well done very obvious why your so happy Smiley
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JWallin
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« Reply #16 on: May 12, 2011, 11:29:33 AM »

Hmmm, I'd be suprised if the cost wasn't at least twice that $1800.00. The typical rule of thumb for residential installations using crystilline silicon technology runs about 6.50 - 7.00/watt. Even at 5.00/watt that 600 watts will run 3K. Add in the cost of replacing your batteries periodically and it's even more. There is really no return in the US without government incentives unless you lease your equipment and sell excess production back to the grid. If you like the flexible thin film products better, you'll likely need to plan on covering your entire bus because they are only about 12-15% efficient, about half that of silicon.
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JohnEd
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« Reply #17 on: May 12, 2011, 11:35:23 AM »

I used a cheapo inverter to run my cheapo water flow control valves and turn on the circ pump(12VDC) in the house fresh system, for my freeze protection system.  My deep cycle would power that system for a month and the heat came from the hot water heater.  Used some propane but I was protected.  Most expensive component was the Thermostat switch with the long bulb sensor.  I used water control valves out of common washers that ran off of 120AC.

John
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« Reply #18 on: May 12, 2011, 11:37:35 AM »

Hmmm, I'd be suprised if the cost wasn't at least twice that $1800.00. The typical rule of thumb for residential installations using crystilline silicon technology runs about 6.50 - 7.00/watt. Even at 5.00/watt that 600 watts will run 3K. Add in the cost of replacing your batteries periodically and it's even more. There is really no return in the US without government incentives unless you lease your equipment and sell excess production back to the grid. If you like the flexible thin film products better, you'll likely need to plan on covering your entire bus because they are only about 12-15% efficient, about half that of silicon.

Now that is INTERESTING.  ASll of what he said.

John
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"An uneducated vote is a treasonous act more damaging than any treachery of the battlefield.
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« Reply #19 on: May 12, 2011, 11:46:50 AM »

I am surprised that someone did not link this to some of the more recent threads on the subject.

There was a lot of discussion in this thread:

http://www.busconversions.com/bbs/index.php?topic=19713.msg

There was some pretty good information there.  I detailed my system and noted that I did not feel that it was a good investment for our situation.  Too much to post again.  

Sean is tied up right now with the Red Cross activity, but his has had some good input on the subject.  Here is one of many threads:

http://www.busconversions.com/bbs/index.php?topic=17047.0

I am always concerned about what I call "amateur calculations".  I don't mean that to be derogatory, but the application calculations for this technology is pretty complex.

There are a ton of variables that need to be factored in to get even remotely close to realistic energy calculations.  For example, you need to factor in actual sun days, hours of sun exposure, efficiency of absorption of energy, efficiency of energy conversion, etc.  By far the biggest factor is how well you aim the panels.  On our vehicles, that is a real challenge.  If you flat mount the panels, you loose a ton of "efficiency".

If you have some sort of system to point the panels, you still have an issue with parking the vehicle in a position for maximum absorption.  At one trade show, I saw a unit that tracked the sun and elevated the panels to maximize the "efficiency".  The price was pretty steep, but might be worth it for some folks.  I have not seen them at recent shows, so maybe they folded.

This is a very big investment and there is not a single answer.  Each person must justify the cost based on their factors.

Jim

« Last Edit: May 12, 2011, 03:26:14 PM by rv_safetyman » Logged

Jim Shepherd
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« Reply #20 on: May 12, 2011, 02:42:54 PM »

PVCCESS or Tom,  has installed solar on the roof of his bus.  He keeps his bus in the lower 48 but he lives in Alaska.  I think his bus stays in storage for 6 months or so.  His bats are topped up and ready to go when he puts the key in the door.  He couldn't do that without some sort of pole power and that storage is spendy.  I see his application as the baseline need for service......keep the bats charged while you are away.  Then all this other stuff enters my concern.  I can live with my genny running for a few mins every day.  Loosing a bat will mean I will have to run my genny a couple times a day.  Lots of malfunctions I can work around but long term storage isn't one and bats left discharged will cost ya big time.  And, I am poor.

And what about those wind mills?

John
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« Reply #21 on: May 12, 2011, 07:53:47 PM »



I am always concerned about what I call "amateur calculations".  I don't mean that to be derogatory, but the application calculations for this technology is pretty complex.


  Your probably refering to my amature calculations, and even if your not, your right, im sure the calcualtions needed to figure it out are quite complex. However, once someone has a system working, it is not hard at all to look at it and see what its doing, or copy it. If the guy is running his fridge 24/7/365, then its quite easy to conclude the system is delivering X watts to that fridge.

  I also believe that if you build in extra capacity, and derate your need, you should make enough power to keep it going no matter which way your aimed. For example, 600 watts worth of panels running a 100 watt load wouldnt matter so much which way they were pointed. 
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rv_safetyman
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« Reply #22 on: May 12, 2011, 08:36:56 PM »

Paul, I was not taking a shot at you.  Lots of folks take a quick cut at trying to analyze the subject and don't take all of the factors into consideration.  I was just trying to say that the impact of the variables are pretty darn complex.

For example, Gary (boogiethecat) lives in the San Diego area.  He has a lot more sun days and a better year around "sun angle" than someone in Oregon or Washington.

He specifically mentions that his refrigerator is a "Summit".  I think that manufacturer is pretty efficient compared to an el cheapo unit.  We also don't know what size his unit is.  Gary does not have kids holding the door open all day.  

I think you get the idea of what I am trying to say.

Yes, it would be fairly straight forward to instrument a coach with an integrating watt meter and measure consumption for that coach over a fairly long test period.  But that is the problem.  Each of us has a vastly different energy demand.  Part of that is lifestyle, part is the coach itself, and part is the geographic/climatic condition.  

As I mentioned in the other thread, I have followed the Colorado State University solar technology program a bit over the past thirty years, and my mind boggles at the immense amount of technology involved.  That is the geek side of the picture.  I have wanted to spend some time on the various off-grid related sites (grass roots technology), but never can find the time.  Probably some very interesting stuff there.

The investment is well into to thousands for a good system.  My goal here is to play devil's advocate and suggest that folks really do their homework into the many factors that can impact their decision/investment.

Jim  
« Last Edit: May 12, 2011, 08:40:27 PM by rv_safetyman » Logged

Jim Shepherd
Evergreen, CO
’85 Eagle 10/Series 60/Eaton AutoShift 10 speed transmission
Somewhere between a tin tent and a finished product
Bus Project details: http://beltguy.com/Bus_Project/busproject.htm
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« Reply #23 on: May 13, 2011, 05:22:09 AM »

  Theres a neighbor down the road has a small wind generator, I mean small, about a 3 foot fan, and looking at it noted the fan was stuck onto a GM Alternator. Huh  On the other side of his garage roof, where you cant see from the road, he has half the roof covered with solar panels. He said it started with one, and grew. Inside the garage he has a bank of car batteries. None match, but he said their all even and all being charged through a controller. None of its fancy, most of it looks crude/hobbiest, but its working. He has a couple inverters providing AC power to the house on seperate panels, said all his TV/audio/video is running solely off his system, as are most of his lights, all the garage lights, garage door openers, and his refrigerator. He said the wind electrics were what he started with, but the solar has so greatly surpassed them he no longer uses them.

  While on the one hand this stuff appears greatly complex and difficult to calculate, on the other hand this guy has shown that you can just start building and working it out as you go. The parts are readily available, getting cheaper by the day, and its not rocket science.

  My thoughts for the Bus, if I could do it economically, would be to cover the entire roof with panels that fit the contour, and accept whatever it could deliver. No matter what it provided, any time it took away from running the generator would be some kind of payback.
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happycamperbrat
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« Reply #24 on: May 13, 2011, 09:28:29 AM »

Yes, I know what you mean about wanting to just cover the roof with panels and get what you get. The contour of our curved roof doesnt go great with flat panels either... That's one reason I was looking into making my own panels. Instead of the usual rectangles they could be rows, so it was kinda striped up on top of the bus and kerfed going around. The air gap created would help with insulation too. Maybe spoilers or something could be added up there to help wind resistance......
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« Reply #25 on: May 13, 2011, 09:39:01 AM »

CamperBrat
 Where were you looking to source your cells from? The process of building a custom array intrigues me.

Brice
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JWallin
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« Reply #26 on: May 13, 2011, 10:22:19 AM »

For what it's worth, arrays don't respond well to being partially shaded and generally incur significant losses unless insolation across the array remains nominally equal.
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« Reply #27 on: May 13, 2011, 11:54:35 AM »

For what it's worth, arrays don't respond well to being partially shaded and generally incur significant losses unless insolation across the array remains nominally equal.

  just so im understanding you, are you saying the shaded cells suck power away from the producers? Couldnt the roof be made up of many mini cells, all connected in groups, then each group routed to some type of controller or bank of diodes? I thought if I was ever dumb enough to cover the roof with solar cells, odds are its going to get damaged by falling branches, hail, etc., so best to think small cells rather than large big dollar ones. 
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JWallin
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« Reply #28 on: May 13, 2011, 02:02:41 PM »

When even a small portion of a cell, module, or array is shaded, the output falls dramatically due to internal short-circuiting which results in heat being produced instead of power. Most individual panels contain bypass diodes to reduce this effect. Solar panels are many "mini cells" grouped togeather and routed to some type of controller. So while different configurations may influence both initial and ongoing balance of system costs, shading remains a consideration.

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happycamperbrat
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« Reply #29 on: May 13, 2011, 08:42:47 PM »

CamperBrat
 Where were you looking to source your cells from? The process of building a custom array intrigues me.

Brice


Hi Brice! My brother is getting them from ebay... they sell them single celled. Watch the packaging though when buying this way. They are extremely fragile, kinda like handling a saltine cracker so they can break very easily.
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